where \(c\) , \(\beta \) , \(x_k\)  are real numbers, \(\alpha \ge 0\) , \(m\)  is a nonnegative integer and \(\sum x_k^{-2}<\infty \) . For more background on the theory of the
\(\mathcal {LP}\)  class, we refer to [1]} and [2]}.
